Ideal add-on to your CCTV DVR System. Simply plug into your DVR Audio Channel using a Phono Cable. It requires a 12V power supply. It’s used both Indoor and Outdoor (Outdoor with suitable protection from the rain). 2 Connectors: One is a phono connector for audio while the other one is a DC power connector. Can be fitted on ceilings, walls, in suspended ceilings, under roofs, under soffits, cashier/ till desk at your business, behind a sofa inside a living room, etc. Connects directly to you DVR, no need for an amplifier.